High-pressure container safety means



June 12, 1962 H. s. DALEY SURE CONTAINER SAFETY MEANS Y HIGH-PRES Filed May 51, 1960 m T. m m

United States Patent 3,038,627 HIGH-PRESSURE CONTAINER SAFETY MEANS Horace S. Daley, Clifton, N.J., assignor to Specialties Development Corporation, Belleville, N311, a corporation of New Jersey Filed May 31, 1960, Ser. No. 32,785 5 Claims. (Cl. 220-3) The present invention relates to metallic containers for confining a gas under high pressure, and, more particularly, to such containers formed with wall structure which serves as a safety valve.

Gases such as carbon dioxide, nitrogen, oxygen and air are usually confined under pressures of between about 1000 and 3000 p.s.i. in a cylindrical container formed of a ferrous alloy which is subject to corrosion. In certain uses of such containers, for example, where compressed air is utilized for underwater diving or elsewhere for breathing, it is essential that the air contains some humidity to avoid discomfort on the part of the person breathing the air.

It has been demonstrated that at even relatively low humidities of about between 40% and 50% under standard atmospheric conditions will result in water being deposited in the container when such air is compressed to between about 1000 and 3000 p.s.i. A portion of this water remains in the container after the air has been used and the accumulation increases with each filling of the container. Frequently, containers used with diving equipment are filled near a body of water where higher humidi ties prevail, whereby the water accumulation will be even higher and more rapid.

Such accumulations of water will cause corrosion at the inner wall of the container, and eventually the wall will be materially corroded and weakened at one point to an extent whereby the pressure of the gas will burst the container with violence. While safety regulations require that such containers be hydrostatically tested periodically, failure under rapid corrosion conditions has occurred before the time the test was required.

Accordingly, an object of the present invention is to provide a container which will not burst with violence when wall portions are weakened by corrosion.

Another object is to provide such a container wherein wall structure is formed which serves as a safety valve to release gas under pressure without violence.

A further object is to provide such structure which is simple and practical and can be formed without increase in the cost of the container or adverse effect on the container to perform its normal function.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

In accordance with the present invention, it has been found that the foregoing objects can be generally accomplished by providing a container which comprises a side wall, and a bottom wall having means for standing the container in an upright position whereby water will collect on the bottom wall at the interior thereof and the bottom wall having recess means for collecting the water provided with a portion of reduced wall thickness adapted to be contacted by the water and adapted to be corroded to weaken the same to cause pressure of the gas to burst the portion of reduced thickness while leaving the remainder of the container intact.

A preferred embodiment of the invention has been chosen for purposes of illustration and description, and is 2 shown in the accompanying drawing, forming a part of the specification, wherein:

FIG. 1 is a bottom plan view of a container in accordance with the present invention.

FIG. 2 is a fragmentary sectional view taken along the line 2-2 on FIG. 1.

FIG. 3 is an enlarged fragmentary sectional view of the wall portion of reduced thickness.

Referring to the drawing in detail, there is shown a container which generally comprises a side wall 10, a bottom wall 11, and a dome 12 at the upper end provided with a spud 13 formed with an opening 14 for receiving a valve (not shown).

By way of example, the present invention can be practiced by modifying a high-pressure container such as shown in United States Patent No. 2,541,065, February 13, 1951. Such a container as shown herein has a cylindrical side wall 10 and a hemispherical dome 12 of substantially uniform wall thickness adapted to safely confine high pressure gas, and has a generally ellipsoidal outwardly formed bottom wall 11 provided with radial formations 15 extending axially outwardly out of the bottom Wall a relatively short distance beyond the center portion of the bottom wall which formations serve as means for standing the container in upright position. The bottom wall has a thickness at least equal to the thickness of the side wall and the dome.

For example, six circumferentially spaced formations 15 may be provided which are generally pear-shaped and have a generally spherical external knob 16 at their radially outwai'd end. These knobs provide recesses 17 at the interior which, in accordance with the present invention, have a concave portion of reduced wall thickness 18 at the lowermost part thereof in which water can collect and localize the most rapid corrosion which may occur at these portions. By reason of the general spherical shape and small diameter of the knobs, the wall thickness can be reduced to a small fraction of the normal bottom wall thickness without weakening the container at that point.

As a specific example of the present invention, a container was constructed in accordance with the following specifications:

Material Chrome moly steel Capacity cu. ins 646 Height ins 23 Diameter ins 6.5 Weight lbs 21 Wall thickness, side and dome ins .135 Wall thickness, bottom ins .135 Minimum wall thickness portions 18 ins .090 Area of portion 18 sq. ins .785

This container was equipped with a valve and was charged with compressed air at 2000 p.s.i. Corrosion was simulated by exteriorily abrading the container at one of the portions 18; and, when the wall thickness of this portion was reduced whereby the portion was weakened sufiicien'tly so that it could not withstand the pressure within the container, a small puncture was produced in the bottom wall at the portion 13 and the compressed air escaped through the opening thus formed without further disruption of the container. This test was repeated four times with the same result in each instance, thereby demonstrating that the portions 18 act as safety valves when further thinned out as would occur by localized corrosion due to water being constantly in contact therewith at the interior.

It is also contemplated that the present invention can be utilized in connection with containers which are at most times positioned so that water will collect at the bottom thereof.

From the foregoing description, it will be seen that the present invention provides an improved container which will not be disrupted upon weakening by corrosion and therefore eliminates the dangerous hazard to which users of such high-pressure containers were previously subjected if progressive type failurewereto occur.

As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

I claim:

1. A container for confining a gas in its gaseous state under high pressure constructed of corrodable metal and inherently subject to containing a sufiicient quantity of water to cause corrosion at the inner walls thereof, which container comprises a side wall, and a bottom wall having means formed therein for standing the container in an upright position whereby water will collect on said bottom wall at the interior thereof and said bottom wall having means having internal recess means for collecting the water, said recess means being provided with a portion of reduced wall thickness normally capable of safely withstanding the working pressure of the gas and being contacted and corroded by the water to weaken the same to cause the pressure of the gas to burst said portion of reduced wall thickness to release the gas externally of the container before other portions of the container walls can be corroded to materially weaken the same to an extent whereby the pressure of the gas can burst the container with violence, whereby said portion of reduced wall thickness serves as a safety valve to enable the container to eventually fail safely.

2. A container for confining a gas in its gaseous state under high pressure constructed of corrodable metal and inherently subject to containing a suflicient quantity of water to cause corrosion at the inner walls thereof, which container comprises a side wall, and a bottom wall having a plurality of means formed therein for standing the container in an upright position wherby water will collect on said bottom wall means at the interior thereof and said bottom wall having internal recess means for collecting the water, each of said recess means being provided with a portion of reduced wall thickness normally capable of safely withstanding the working pressure of the gas and eing contacted and corroded by the water to weaken the same to cause the pressure of the gas to burst at least one of said portions of reduced wall thickness to release the gas externally of the container before other portions of the container walls can be corroded to materially Weaken the same to an extent whereby the pressure of the gas can burst the container with violence, whereby said portion of reduced wall thickness serves as a safety valve to enable the container to eventually fail safely.

3. A container for confining a gas in its gaseous state under high pressure constructed of corrodable metal and inherently subject to containing a sutficient quantity of water to cause corrosion at the inner Walls thereof, which container comprises a side wall, and a bottom wall having means formed therein for standing the container in an upright position whereby water will collect on said hottom wall means at the interior thereof and said bottom wall having a plurality of uniformly circumferentially spaced internal recess means for collecting the water, each of said recess means being provided with a concave portion of reduced wall thickness normally capable of safely withstanding the working, pressure of the gas and being contacted and corroded by the water to weaken the same to cause the pressure of the gas to burst at least one of said portions of reduced wall thickness to release the gas externally of the container before other portions of the container walls can be corroded to materially weaken the same to an extent whereby the pressure of the gas can burst the container with violence, whereby said portion of reduced wall thickness serves as a safety valve to enable the container to eventually fail safely.

4. A container for confining a gas in its gaseous state under high pressure constructed of corrodable metal and inherently subject to containing a sufficient quantity of water to cause corrosion at the inner walls thereof, which container comprises a side wall, and a bottom wall having means formed therein for standing the container in an upright position whereby Water will collect on said bottom wall at the interior thereof and said bottom wall means having internal recess means for collecting the Water, said recess means being provided with a portion of reduced wall thickness of about two thirds of the thickness of the wall portions adjacent thereto, which portion is normally capable of safely withstanding the working pressure of the gas, said portion of reduced wall thickness being contacted and corroded by the water to weaken the same to cause the pressure of the gas to burst said portion of reduced wall thickness to release the gas externally of the container before other portions of the containerwalls can be corroded to materially weaken the same to an extent whereby the pressure of the gas can burst the container with violence, whereby said portion of reduced wall thickness serves as a safety valve to enable the container to eventually fail safely.

5. A container for confining a gas in its gaseous state under high pressure constructed of corrodable metal and inherently subject to containing a sufiicient quantity of water to cause corrosion at the inner walls thereof, which container comprises a side wall, and a bottom wall adapted to be positioned so that water will collect on said bottom wall at the interior thereof and said bottom wall having internal recess means for collecting the water provided With a portion of reduced wall thickness normally capable of safely withstanding the working pressure of the gas and being contacted and corroded by the water to weaken the same to cause the pressure of the gas to burst said portion of reduced wall thickness to release the gas externally of the container before other portions of the container walls can be corroded to materially weaken the same to an extent whereby the pressure of the gas can burst the container with violence, whereby said portion of reduced wall thickness serves as a safety valve to enable the container to eventually fail safely.

References Cited in the file of this patent FOREIGN PATENTS 610,752 Germany Apr. 8, 1934 t he 

